Aer Lingus operated via Manchester from the 50s through to the early 70s in the pooling environment where revenues and timetabling were shared across much/most/all the European flag carriers.
These arrangements were to come to an end when around 1983 due to EEC competition laws.
Around the early nineties they had another go of fifth/sixth freedom operations via Manchester to Hamburg/Zurich/Paris/Milan/Copenhagen and another German port . They also flew Bristol- Brussels -These were commercial operations however didn't last long.
Money makers they weren't
Aer Lingus have also operated briefly a daily A333 service to New York JFK but can't remember the time frame.
TSR3 SAS have operated the Manchester- Copenhagen leg continuously since 1968 with Caravelle and DC9 through the MD80 to the A320 and Canadajets today.
By the way the SAS DC-9s were usually model 40s slightly longer than the series 30 and very rarely the stubby series 20. Only series 30s SAS operated and they visited Manchester regularly were two Freighters.
In fact they went daily except Saturday when pooling ended and the Dublin tag disappeared.
Interestingly Sterling also operated on the Copenhagen- Manchester- Dublin sector with a Caravelle on summer Wednesday and Saturdays in the early seventies as well.